A few questions for world-class Ornithologist Jack Hailman about JIC Bird Species Populations
(Professor Emeritus of Zoology, University of Wisconsin, and Research Associate, Archbold Biological Station, Venus, Florida)
How can JIC residents support a vibrant bird population?
Plant more natives and fewer horticultural species that require poisons to protect them from insects. More native plants mean more native insects, better cover for birds, better roosting places, better nest sites, and because they need less water, lower water bills!
What about herbicides and pesticides? Despite the “green” labeling, do they still harm the bird population?
Yes, definitely. We cancelled our "pest control" contract years ago despite the company's prediction of dire consequences. There's never been a problem. We poison only chinch bugs, and will be as long as small grandchildren play on our lawn.
There's no such thing as a truly species-specific herbicide or pesticide; they all kill things other than what the company tells you. Killing our native insects deprives insectivorous birds of their food. Likewise, killing native plants both eliminates their insects and deprives herbivorous birds of their food. The average amount of poison used per square yard in suburbia greatly exceeds that of agricultural fields.
After a feral cat’s body was found recently, a bobcat was trapped. Do bobcats threaten birds?
Bobcats typically take mammalian prey (rabbits, squirrels, opossums, raccoons). Birds are pretty small prey for a bobcat.
Are feral cats a threat?
Yes. But feral cats aren’t the only predators. House cats are too. It’s difficult to persuade cat owners to keep their pet cats in at night when they hunt. We have always had cats. And they were allowed to come and go. After Stanley Temple of the University of Wisconsin published his landmark study based on radio tracking of his own cat at night, we re-thought our habits and kept our cats in the house. They didn't like it at first, but cats are smart and they lived to a good old age.
Does feeding birds help or hurt bird populations?
It’s more or less neutral. We have exotic House Sparrows at our feeder that only a few years back were absolutely unknown in the Colony. They chase our female Painted Buntings off the feeders. European Starlings, also once unknown here, now congregate in flocks that seem to grow larger each year.
How is our pelican population?
Last winter was a banner year with a very high proportion of young birds, reflecting an unusually successful 2010 breeding season. Mortality is higher in immature birds so there should be fewer pelicans this year than last, but the population seems about normal.
But pelicans are a species to watch. The oil disaster in the Gulf will take years to manifest itself. The oil has settled on the bottom, where it will smother benthic organisms. This die-off will work its way up the food chain, eventually causing declines in fish populations, and only then will fish-eating birds such as Brown Pelicans and Ospreys show the effects. The two uncertainties are how long this will take and how large the effects will be. It's not a pretty prospect.
You and Liz do a species count in JIC every year. How are our counts holding up?
Our birds have decreased markedly. See the chart for our annual species tallies for JIC:
We were recording roughly 100 species per year through 2006, but that dropped to 87 in 2007, and it is been in the 70's ever since. We have lost a quarter of our species. No cheers about that.
Why the decline?
Over the last couple of decades empty lots in JIC are now built upon, eliminating remnants of native vegetation and diminishing the food supplies, roosting sites, and nest sites. Global warming may mean some of our wintering birds no longer come this far south. We have a substantial feral cat population. There is not yet any documentation of a general decline of birds in South Florida, but if there is such a decrease, then peripheral habitats like suburban areas would be expected to show it before more natural habitats do.
Any new birds in JIC??
We’ve had consistently White-winged Doves this winter. White-wings stay pretty much in citrus groves. Why they've been common in the Colony this winter, I don't know. We have also had a White-throated Sparrow, which arrived in late November and stayed the winter. We suspect he'll soon migrate north.
Will the removal of utility wires have any impact on our birds’ behavior?
The birds should do just fine, but no wires will put a kink in the bird-watching! Birds will just have to perch in trees and on houses. They might sing that song: got along without you before I met you, gonna get along without you now.